[Dnsmasq-discuss] How does blocking domains work

[joe barbish]

Hello List.

I understand that adding this statement on a single line to the conf file will block it.
server=/facebook.com/

There are many sites that maintain lists of domain names of sites for blocking known ad, tracking and other malware domains. Combining these lists together results in a list containing 50,000+ single line records.

My question is how does dnsmasq internally handle a file of this size?

Is this file read one time at startup and kept in a binary searchable table for super fast lookup?
Are the server=/xxx/ records read sequentially every time for each dns request?

Thanks
Joe